the documentation of [ and OR in the manual. The reason is that the
esc-sequences table contains words [ and OR and these were getting put into
doc/doc.fd and then slipped into the .tex file in preference to the correct
entries from doc/crossdoc.fd
My less-than-ideal fix to this is to add "[IFNDEF] put-doc-entry" around
the definition of the esc-sequences so that it gets omitted completely
during a documentation build. The ideal fix would be for crossdoc.fs and
the prim->index process to each support optional "prefix-" in the same
way that doc/makedoc.fs does.